I believe that if you want to improve your brewing, one of the most important things you can do is to learn to evaluate beer in a professional way. You need to learn to evaluate beer in a descriptive and consistent way, and be able to link the evaluation of the beer through to your recipe/method and notes from when you brewed the beer. Being able to figure out what changes in ingredients and brewing method does to the beer flavours is how you will learn to be able to formulate beers the way you want to.
Below is a quick guide on how to judge beer from the BJCP website. It is based on the BJCP method, and scoresheet which is what is used in most brewing competitions. Probably a great idea to run through tasting a few beers along with this judging sheet to get a feel for it. http://www.bjcp.org/docs/Beer_checklist.pdf
How to Judge Beer
By Peter Garofalo
1. Fill in the scoresheet header, including information about the beer and yourself.
2. Examine the bottle. Look for tight sediment (good), or excessive sediment (a possible sign of infection). Note the fill level: too high may result in low carbonation; too low (>1.5”) may allow oxidation. Look for any rings around the bottle neck, which is another sign of contamination. Check the box if appropriate, or add some comments.
3. Open the beer and pour out 1-3 ounces, raising a solid head if possible. Immediately sniff the beer to capture the aromatics. Use long, deep sniffs or short, shallow sniffs–which ever works best for you, but be consistent for all beers judged.
4. Write down initial aromas. Follow the cues under the Aroma section: malt, hops, esters, and other aromatics. A complete scoresheet must contain comments on each aspect. Try to be specific: is the malt caramelly, toasty, roasty, burnt…? Are the hops fresh, floral, earthy, citrusy…? If esters are present, what fruits do they evoke: berries, cherries, pears, plums…? Be sure to note the presence (or absence) of expected characteristics for the style. For example, a German hefeweizen should have banana ester and clove phenolics.
5. Move on to Appearance: Comment on the beer’s color–try to name it specifically: golden, amber, copper, brown, black, etc. and relate it to style expectations. Note the clarity: cloudy, turbid, clear, sparkling, opaque. Again, what does the style call for? Finally, note the head characteristics: color, bubble size, retention. Does it stand firmly or collapse quickly?
6. Now, taste the beer. Form an initial impression from the first sip, and allow it to linger a few seconds before swallowing. Note the finish (as you swallow) and aftertaste (a few seconds later). Pay attention to the cues under Flavor: malt, hops, fermentation characteristics, balance, finish/aftertaste, and other flavor characteristics. As under Aroma, try to specifically identify the type of malt, hops, esters (if present). Note the presence or absence of DMS and diacetyl, or other characteristics such as oxidation, sourness, sweetness, solvent character, etc. If present, are they appropriate? Be sure to note the balance from start to finish, and through to aftertaste. The best beers will remain in balance throughout.
7. Move on to Mouthfeel, assessing the beer’s body (thin, watery, medium, full, thick), carbonation level, alcoholic warmth, astringency, and other sensations. Be sure to note whether the attribute is appropriate for the style at hand.
8. In the Overall Impression section, give a general impression of the beer. Try to avoid personal pronouns (I think…), and give objective comments on how the beer fits the intended style. If flaws are noted, point to possible causes.
There are several important points to keep in mind throughout the judging process. First off, avoid negative comments. Emphasize the beer’s positive attributes, even if it is awful. Diplomacy is a valuable skill as a beer judge. Also, try not to be too specific, since you do not know how the beer was brewed. If there is a malt-related issue, be sure any advice applies to either all-grain or extract brewers.
As for scoring, there are two major methods: top-down and bottom-up. Top-down scoring means that you decide where the beer should score overall, and fill in the sections to add to that total. Bottom-up refers to the practice of filling in a score for each section and adding them to a final score. Either way, the score should make sense. Use the Scoring Guide on the lower left hand side of the scoresheet as a sanity check.
Use the check boxes on the left-hand column of the scoresheet as a list of beer characteristics to comment on. Check all boxes that apply as you score the beer. Note whether the characteristic is appropriate or not for the style.
Use the check boxes on the lower right side of the scoresheet to give the entrant additional information. These are simply to inform the brewer of strengths and weaknesses in a broad manner: stylistically, technically, and in terms of intangibles.
Note that an experienced beer judge should be able to complete an evaluation in about ten minutes. The scoresheet should be completely filled in, legible, and added correctly.
Finally, the most important thing that a good beer evaluation should provide is a thorough sensory evaluation. Keep opinions to yourself, and make sure the entrant understands just what attributes the beer has (or doesn’t have) that justify its score.
If entering your beer into competitions, then you need to pay close attention to the style descriptions. You can have a great beer, but if it is entered in the wrong category, or has characteristics that do not fit in the category it will not score well. If you are brewing beer for your enjoyment and have no intention of entering competition, then the style guides give a common language of how to describe what sort of beer you are talking about. If the beer is not for competition then you are free to brew beer that tastes how you would like it to, and you do not have to worry if it does not actually fit in any of the current categories! This is when you can innovate and come up with new beers like a Black IPA.
If you want more information on how to judge beer then the BJCP website has all the info you need! http://www.bjcp.org/index.php